# Slurm

## Slurm's architecture

Slurm is made of a slurmd daemon running on each compute node and a central slurmctld daemon running on a management node.

**Node**

In slurm a node is a compute resource, usually defined by particular consumable resources, i.e. cores, memory, etc…

**Partitions**

A partition (or queue) is a set of nodes with usually common characteristics and/or limits. Partitions group nodes into logical sets. Nodes are shareable between partitions.

**Jobs**

Jobs are allocations of consumable resources from the nodes and assigned to a user under the specified conditions.

**Job Steps**

A job step is a single task within a job. Each job can have multiple tasks (steps) even parallel ones.


## Common user commands:

- [__sacct__](https://wiki.incd.pt/books/manage-jobs/page/sacct): report job accounting information about running or completed jobs.

- [__salloc__](#salloc): allocate resources for a job in real time. Typically used to allocate resources and spawn a shell. Then the shell is used to execute commands to launch parallel tasks.

- [__sbatch__](#sbatch): submit a job script for later execution. The script typically contains the tasks plus and the environment definitions needed to execute the job.

- [__scancel__](https://wiki.incd.pt/books/manage-jobs/page/scancel): cancel a pending or running job or job step.

- [__sinfo__](https://wiki.incd.pt/books/manage-jobs/page/sinfo): overview of the resources (node and partitions).

- [__squeue__](https://wiki.incd.pt/books/manage-jobs/page/seueue): used to report the state of running and pending jobs.

- [__srun__](https://wiki.incd.pt/books/manage-jobs/page/srun):submit a job for execution or initiate job steps in real time. The srun allows users to requests consumable resources.